CHAPTER 2 Flashcards
scientific method
a procedure for using empirical evidence to establish facts.
theories
hypothetical explanations of natural phenomena.
hypothesis
a falsifiable prediction made by a theory. The word falsifiable i
empirical method
a set of rules and techniques for observation.
operational definition
a description of a property in measurable term
construct validity
the extent to which the experiment is testing what it is supposed to
power
ability to detect differences or changes in the magnitude of a property,
reliability
a detector’s ability to detect the absence of differences or changes in the magnitude of a property
demand characteristics
those aspects of an observational setting that cause people to behave as they think someone else wants or expects.
naturalistic observation
a technique for gathering scientific information by unobtrusively observing people in their natural environments.
observer bias
the tendency for observers’ expectations to influence both what they believe they observed and what they actually observed.
double-blind study
a study in which neither the researcher nor the participant knows how the participants are expected to behave
population
a complete collection of people
sample
a partial collection of people or animals or things drawn from a population.
frequency distribution
a partial collection of people or animals or things drawn from a population.
normal distribution
a mathematically defined distribution in which the frequency of measurements is highest in the middle and decreases symmetrically in both directions.
Two Kinds of Descriptive Statistics
The most common descriptive statistics describe a frequency distribution’s central tendency (where do most of the measurements lie?) and variability (how much do the measurements differ from one another?).
mode
value of the most frequently observed measurement)
mean
average value of all the measurements
median
value in the middle
positively skewed distribution
graph has a higher point on the left
range
the value of the largest measurement in a frequency distribution minus the value of the smallest measurement.
standard deviation
how each of the measurements in a frequency distribution differs from the mean.
variables
properties that can take on different values
correaltion
variations in the value of one variable are synchronized with variations in the value of the other.
correlation coefficient
a mathematical measure of both the direction and strength of a correlation,
-1 -> 1
perfect positive correlation = 1
no correlation= 0
natural correlation
the correlations we observe in the world around you
third variable problem
the natural correlation between two variables cannot be taken as evidence of a causal relationship between them because a third variable might be causing them both
experimentation
a technique for establishing the causal relationship between variables.
manipulate the independent
measure the dependent variable
compare value of variables in different conditions
manipulation
a technique for determining the causal power of a variable by actively changing its value
self-selection
a problem that occurs when anything about a participant determines the participant’s condition;
random assignment
a procedure that assigns participants to a condition by chance.
internal validity
an attribute of an experiment that allows it to establish causal relationships.
external validity
an attribute of an experiment in which variables have been operationally defined in a normal, typical, or realistic way
case method
a procedure for gathering scientific information by studying a single individual.
random sampling
a technique for selecting participants that ensures that every member of a population has an equal chance of being included in the sample.
replication
n experiment that uses the same procedures as a previous experiment but with a new sample from the same population.
type 1 error
hen researchers conclude that there is a relationship between two variables when in fact there is not
type 2 error
when researchers conclude that there is not a relationship between two variables when in fact there is
ethical code
informed consent
freedom from coercion
protection from harm
risk-benefit analysis
deception
debriefing
confidentiality
informed consent
a verbal agreement to participate in a study made by an adult who has been informed of all the risks that participation may entail.
